When does a human mutation occur

What mutations are there?

The gene mutation

The term gene mutation refers to the mutation of a single gene. This type of mutation is very common. The gene can be changed in different ways. This includes the Point mutation, the Deletion or the Insertion

What is a point mutation?

The point mutation occurred when one base pair was exchanged for another. One also speaks of a substitution of the base pairs. This exchange can have different effects. There is the so-called mutePunk mutation. Here we have a change in the gene, but there is no consequence with regard to the gene product. This means that on the one hand we have a different base pair in the genome, which then also leads to a different codon. On the other hand, the same amino acid is still produced during translation (more on this: wobble theory).
The counterpart to this is that Missense mutation. This type of mutation is understood to be a base exchange, which ultimately also results in the translation into another amino acid. This leads to a different protein doing a different job, hence mis-sense.
Should it happen that the changed region on the genome becomes a Stop codon leads is called this Nonsense mutation. This often leads to a protein that is much too short and inoperable, hence nonsense.

The effects of deletion and insertion

A deletion is the loss of part of the gene. In contrast to this, the insertion means that a certain part is inserted. The two mutations result in a shift in the reading frame during translation. For this reason they are also called Reading frame mutations.

The chromosome mutation

When the chromosome is mutated, the structure of the chromosome is changed. There are different types of chromosome mutations that we will now show you.


Deletion involves removing a specific area of ​​the chromosome. A few, but also many nucleotides can be affected.


The duplication of a chromosome segment.


During inversion, a specific section of DNA is cut out. This then rotates 180 ° and then ties again in the same place. It is now in the reverse direction of reading.


Insertion involves adding a few pairs of brooms from one strand of DNA within another.


Change of the localization of a chromosome segment on chromosome A towards a new localization of the same chromosome segment on chromosome B.

Fusion and Fission

If chromosomes are attached to your Centromere break apart, this mutation is called fission. If, on the other hand, the chromosomes fuse at their centromeres, this is called fusion.

The genome mutation

If there is a genome mutation, then there has been a change in the total number of chromosomes in the organism.

The basis of a genome mutation is Nondisjunction (i.e. the chromosomes not diverging) during meiosis. A distinction is essentially made between two types of genome mutation, which we will now describe in more detail.


In polyploidies, the set of chromosomes is not in the normal way. That would be a diploid proposition. In this type of mutation, the set of chromosomes is multiple, i.e. polyploid. Wheat 6n; Strawberries 10n; Disturb 8n


Some chromosomes are higher or lower than usual in number. An example of this is trisomy 21. Here the said chromosome 21 is present in triplicate. The effects of this mutation are also known as "Down syndrome".

Now you know what kinds of mutations there are. Deepen your knowledge in our exercises. We wish you a lot of fun and success!